Commentary on Conde <i>et al</i>.: Evidence and gap map offer an important opportunity for dialogue and refinement of the gateway hypothesis controversy

The recent Cochrane-affiliated evidence and gap map on the e-cigarette gateway hypothesis creates a valuable opportunity for these well-respected and impartial authors to bridge the divide in opinion by working with all sides to refine definitions of a ‘gateway’ and types of evidence in subsequent research. The question of whether e-cigarette use promotes subsequent cigarette smoking among youth (commonly known as the ‘gateway hypothesis’) is critical for understanding e-cigarettes' net impact on population health. Unfortunately, it is also a highly polarized topic. Not only is there no clear resolution (yet) embraced by both sides [1, 2], but the many studies published on the topic do not seem to have changed anyone's mind. This seems to be a real-life example of the epistemological network model described by O'Connor and Weatherall [3] (see the figures, particularly the polarization one) whereby levels of social trust and conformity are such that more research does not lead to a convergence on truth. We hope that researchers willing to devote the effort and take the risks to work with ‘adversaries’ will draw motivation from peers in other fields taking the same risks and efforts. Arielle Selya: Conceptualization; project administration; writing—original draft; writing—review and editing. Joe G. Gitchell: Conceptualization; writing—review and editing. Through Pinney Associates, A.S. and J.G.G. provide consulting services on tobacco harm reduction to Juul Labs (JLI). A.S. also individually provides consulting services on behavioural science to the Center of Excellence for the Acceleration of Harm Reduction (CoEHAR) through ECLAT Srl, which received funding from the Foundation for a Smoke-Free World (FSFW; now the Global Action to End Smoking [GA]). Neither JLI, CoEHAR, nor FSFW/GA had any role in, or oversight of, this commentary.